Underwater device having an acoustically isolated nose section



INVENToRs vANcE F. Bosweu. JAMES c sHAw AT o N Y FIG 3. m B F June 30, 1964 v. F. BoswELL. ETAL UNDERW'IEIP DEVICE HAVING AN ACOUSTICALLY ISOLATED NOSE SECTION Filed Jan. 10, 1961 FIG.|

United States Patent O 3,139,056 UNDERWATER DEVICE HAVING AN ACOUSTI- CALLY ISOLATED NDSE SEC'HGN Vance F. Boswell, Rocky River, and .lames C. Shaw,

Lorain, Ghio, assignors to Clevite Corporation, a corporation of Ohio Filed dan. 10, 1961, Ser. No. 81,897 6 Claims. (Cl. 114-22) This invention relates to a class of underwater devices commonly referred to as mobile targets, underwater decoys, acoustic torpedoes, acoustic beacons and the like, and more particularly concerns the physical and acoustic separation of interconnected compartments or sections of such devices.

For ease of illustration and example of such devices reference may be had to U.S. Patent 2,887,671, issued to B. Frankel et al. and assigned to the same assignee. The patent discloses a torpedo-like hull adapted for use as an echo elongator. The device has two spaced apart acoustic transducers for receiving and/ or transmitting sonar pings, one of which is housed in a forward nose section and the other being mounted further aft. Acoustic interference occurs by reason of acoustic energy feed-back from one transducer to the other unit through the hull and as a result the available target size is reduced. Conversely, when transmission of sound through the hull is attenuated the available target size is increased.

It is the primary object of this invention to provide an underwater device including a torpedo-like hull connected to an isolated acoustic nose section in which acoustic feedback energy transmitted through the hull structure of the device to the nose section thereof is eliminated or at least attenuated to an acceptable degree.

Another object of this invention is to provide an acoustic nose section in which an electroacoustic transducer is resiliently mounted to absorb shocks and vibrations to permit air drop or tube launching of the underwater device without damage to the sensitive transducer.

Another object of this invention is to provide a nose section connected to a torpedoelke hull in a manner that prevents transmission of mechanical vibrations existing within the hull to the nose section.

It is another object of this invention to preserve watertight integrity particularly between the nose section and the general hull of the torpedo-like structure under external pressure conditions ranging from a few p.s.i. to 700 p.s.i. or greater.

It is another object of this invention to employ a material exhibiting shock resilient and acoustic isolating qualities and to arrange such material to effect a resilient counterforce regardless of stress application to balance shocks occurring during the launching and operation of the underwater device.

The foregoing objects are accomplished in the preferred embodiment of the present invention by the provision of an underwater device including a torpedo-like hull and an isolated hollow nose section connected thereto in which a frame is suspended within the hollow nose section and an electroacoustic transducer is mounted on the frame. A rubber-like material is secured to and between the nose section and the torpedo-like hull; a rst and a second retaining member are embedded in the rubber-like material and the first member is connected to the nose section, and the second member s connected to the torpedo-like hull.

For a better understanding of the present invention, together with other and further objects thereof, reference is had to the following description taken in connection with the accompanying drawings, and its scope will be pointed out in the appended claims.

Patented June 30, 1964 ICC In the drawings:

FIGURE l is e perspective view of an acoustic torpedo embodying the present invention;

FIGURE 2 is a longitudinal section through the forward nose section of the device illustrating the intermediate rubber-like section and its manner of connecting the nose section to the torpedo-like hull; and' FIGURE 3 is a View similar to FIGURE 2 illustrating a modication of the connection arrangement.

Referring now to the drawings, there is shown an underwater device 11 comprising several sections, including a nose section 13 at the forward end of the device, a torpedolike hull 15 aft of the nose section 13, and an intermediate section 36 facilitating a unique connection `between the nose section and the torpedo-like hull.

The torpedo-like hull has a pressure bulkhead end wall 17 adjacent to thenose section 13. The structure of the hull 15 proximate to the end wall is generally tubular and is provided with a plurality of peripheral grooves 19 and projections 21. The hull carries an electroacoustic transducer which is not shown.

A chamber 23 is formed in the nose section of the underwater device 11 by a generally annular metal member 25 from which projects inwardly a radial retaining flange 27, see FIGURE 2. A llexible resilient rubber diaphragm 29 is secured around the forward end of the metal annulus 25 extending completely across the forward end of the chamber 23; oppositely therefrom a circular frame member 31 is suspended from the metal annulus 25 in iluid tight fashion covering the cross area. The chamber is lled with a suitable liquid, such as castor oil, serving as the transmission medium for acoustic signals. A conventional electroacoustic transducer 33 is secured by welding, or other means, to the frame 31 within the chamber 23. Because of the flexibility of the diaphragm 29 the liquid assumes the same pressure as the sea pressure outside the torpedo.

The pressure bulkhead end wall 17 of the torpedo-like hull 15, as shown in FIGURE 2, is somewhat convex shaped, and near the central axis thereof the end wall supports a retaining plate 3S which is, except for the central portion thereof, spacedly removed from the end wall. The radial ange 27 of the nose section extends substantially perpendicular with respect to the central axis of the annulus and at least portions of the retaining plate 35 are coextensively arranged with the flange. For ease of construction the geometrical relationship between ange 27 and plate 35 is substantially parallel. It is not essential that the flange be integral with the annulus 25, rather the radial flange may extend from or be connected to the frame member.

The nose section 13 is connected to the torpedo-like hull 15 of the underwater device 11 by means of intermediate section 36 formed of a body of rubber-like material 37 which is retainedly molded to and between the frame 31 and the end wall. The peripheral grooves and projections 19, 21 in the hull member 15 facilitate a grip on the rubber-like material. The rubber-like material surrounds the retaining plate 35 and the radial flange 27 which similarly acts as a retaining member, whereby both of the retaining members are deeply embedded in the rubber-like material in opposing relationship as shown.

The rubber-like material is of a character exhibiting resilient and shock absorbing qualities. Preferably, the rubber-like material is formed with a plurality of air cells to attenuate acoustic energy. Material of this type is readily available from customary sources.

Similarly, the structures such as the retaining flange 27, the retaining member 35, the body of rubber-like material 37, etc. increase the number of acoustically unequal boundaries through which the acoustic energy must pass. This produces an impedance mismatch which acoustically isolates the transducer 33 in the nose section from the acoustic energy transmitted through the torpedo-like hull 15.

During the various operating stages of the underwater device such as air launching, breaching (breaking the Ysur- Yface of the water), porpoising (leaving the surface of` the end wall 17 and the frame member 31, `and thetubular member extends through the retaining plate 35 without physical contact therewith. The member 39 is held in position by two tubular sleeves 49, 51 which connect at opposite ends'to the tubular member 39 and, respectively,

to the frame member 31 and the end wall 17. An electric lead line 40 may thus be brought into the chamber 23 to the transducer 33 through the tubular member 39, without affecting the physical and acoustical separation between the nose section and the torpedo-like hull.

In FIGURE 3, the device as aforedescribed is modified to the extent that the retaining flange 27 comprises a retaining structure member 41 extending completely across the annulus 25 and parallel with respect to retaining plate 43. The member 41 maintains no rigid structural contact with the end wall 17, the plate 43 is connected to the end wall 17 by means of bolts 47 projecting'through member 41. Apertures 45 in member 41 are of a dimension to prevent any physical contact between bolts 47 and the member 41 when stresses are applied upon the plate 43.

While there have been described what at present are considered to be the preferred embodiments of this i11- vention, it will be obvious to those skilled lin the art that various changes and modifications may be made therein without departing from the invention, and it is aimed,

therefore, in theV appendedY claims to cover all such i changes and modifications as fallwithin the true spirit and scope of the invention.

We claim as our invention:

1. In an underwater device having a torpedo-like hull section resiliently connected to but acoustically physically separated from a hollow nosev section contiguous thereto and containing an electroacoustic transducer; a body of rubber-like material secured'to .and between said sections; a first and a secondv retaining member at least partly embedded in said rubber-like material, said first member being connectedV to saidhull section andsaidv second member being spacedly arranged relative to said irst member and connected to said nose section, said retaining members being disposed in substantially opposing relationship and effective to counterforce stress application upon said nose section.

2. A device according to claim'l wherein said hull and' said nose sections are substantially tubular and the bodyof rubber-like material extends completely across the substantially circular cross-section of said sections.

3. A device according to claim 2 wherein said rubberlike material is formed with'a plurality of air cells to attenu ate acoustic energy.

4. A device according to claim l land a resilient tubular member between said transducer and said hull section for establishing a resilient and acoustically isolating passageway.

5. Ay device according to claim l wherein said second retaining member is telescopic'ally but spacedly disposed said secondv retaining member is in a complementaryV position.

References cited in the-nie of this patent UNITED STATES PATENTS K 2,504,634 Boschi Apr. 18, 1950 2,889,796 Williams et al. .lune 9, 1959 2,899,923 Daly et al Aug. 1.8, 1959V i 3,010,417 Gardner Nov. 28, 1961 

1. IN AN UNDERWATER DEVICE HAVING A TORPEDO-LIKE HULL SECTION RESILIENTLY CONNECTED TO BUT ACOUSTICALLY PHYSICALLY SEPARATED FROM A HOLLOW NOSE SECTION CONTIGUOUS THERETO AND CONTAINING AN ELECTROACOUSTIC TRANSDUCER; A BODY OF RUBBER-LIKE MATERIAL SECURED TO AND BETWEEN SAID SECTIONS; A FIRST AND A SECOND RETAINING MEMBER AT LEAST PARTLY EMBEDDED IN SAID RUBBER-LIKE MATERIAL, SAID FIRST MEMBER BEING CONNECTED TO SAID HULL SECTION AND SAID SECOND MEMBER BEING SPACEDLY ARRANGED RELATIVE TO SAID FIRST MEMBER AND CONNECTED TO SAID NOSE SECTION, SAID RETAINING MEMBERS BEING DISPOSED IN SUBSTANTIALLY OPPOSING RELATIONSHIP AND EFFECTIVE TO COUNTERFORCE STRESS APPLICATION UPON SAID NOSE SECTION. 